This invention concerns maintaining the temperature and relative humidity of the air within an image forming device.
This invention is related to U.S. Pat. No. 6,334,033 issued Dec. 25, 2001, entitled, “Ambient Atmospheric Pressure Compensation Controller for Pressurized Copy Device,” which is incorporated herein by reference in its entirety.
Certain image forming devices, such as, for example, photocopiers, require a temperature controlled environment for increased operational efficiency. However, introducing air conditioning to such devices presents a potential problem in that water vapor in the conditioned air which is used to control the temperature of the device may condense onto component parts of the device.
In U.S. Pat. No. 4,367,036, a temperature and humidity compensating device uses a temperature sensor to detect the temperature of the photosensitive member. A control means is used to control a source of heat located inside the photosensitive member. The heat source is used to keep the temperature of the photosensitive member above ambient temperature to prevent moisture from condensing on, and absorbed by, the photosensitive member.
In U.S. Pat. No. 5,530,523, sensors are provided near the photosensitive member to measure the temperature and humidity near the outer surface of the photosensitive member. A means for calculating a water vapor density is associated with the measured temperature and humidity. A control unit compares a pre-selected water vapor density with the calculated water vapor density. A control unit activates a heater inside the photosensitive member to prevent forming of dew on the photosensitive member based on the comparison.
In U.S. Pat. No. 4,982,225, an image forming apparatus form an image of high quality even in a highly humid atmosphere. Humidity in the apparatus is detected and a heating means is activated by a controller connected to the humidity detecting means. The microcapsule paper used in the device is heated when the humidity is at or below a certain value.
U.S. Pat. No. 5,144,366 discloses a cooling system for an image forming machine that includes a single temperature sensor to detect the temperature inside of the machine and to control the operation of a cooling fan. The cooling fan is used to lower the temperature inside the machine in accordance with the detected temperature and the number of sheets to be copied.
U.S. Pat. No. 5,206,754 discloses a moisture condensation prevention structure for a laser scanning optical system in an electro-photographic image forming device that includes a device for preventing air from circulating in the laser beam optical assembly casing by separating the casing into different compartments.